1. Field of the Invention
The present invention relates to a data recording apparatus for use with data recording apparatus, such as a single-unit video camera-recorder, a video tape recorder, a magneto-optical disk apparatus, a hard disk apparatus or the like, for example.
2. Description of the Related Art
There is known a single-unit video camera-recorder in which a camera section and a video tape recorder (VTR) section are formed as one body to record a video signal obtained from the camera section on a recording medium, such as a magnetic tape or the like.
In the single-unit video camera-recorder, light of an object obtained from an optical system is radiated on an image pickup screen of a CCD (charge-coupled device), and that light is photoelectrically converted by the CCD to an electrical signal. A video signal is obtained by reading the electrical signal by a read-out circuit or the like. The video signal is processed by a signal processing system in some proper signal processing, such as a gamma correction and a white balance adjustment or the like. Then, the video signal is processed by a recording system in a variety of signal processing for recording and supplied through a recording amplifier to a magnetic head mounted on a rotary drum. The magnetic head records the video signal on a magnetic tape so as to form oblique tracks.
When the video signal from the camera section is recorded, the single-unit video camera-recorder uses a clock signal generated from a read-out circuit used to read a video signal or a recording clock signal locked to an external clock signal. Portable VTRs, for example, separate a synchronizing (sync) signal from an input video signal and effect various processing to record the video signal by the clock signal obtained on the basis of the separated synchronizing signal.
Since the single-unit video camera-recorder uses the recording clock signal locked to the input sign al, if a rotational speed of a rotary drum is fluctuated when the single-unit video camera-recorder is vibrated or shocked in use, there is then the disadvantage that the video signal cannot be recorded on the magnetic tape with a correct magnetic track pattern.
Specifically, if the rotational speed of the rotary drum is increased, then a magnetic track pattern is increased in length. Also, if the rotational speed of the rotary drum is decreased, then the magnetic track pattern is reduced in length. consequently, the video signal cannot be recorded on the magnetic tape normally. If the rotational speed of the rotary drum is fluctuated so that the video signal cannot be recorded on the magnetic tape normally, then the magnetic track pattern is fluctuated, which causes a so-called mis-tracking upon reproduction. As a consequence, the video signal cannot be reproduced from the magnetic tape normally.
If portable recording apparatus represented by the single-unit video camera-recorder, such as a portable VTR (connected to the camera and carried in user's waist in use) and a variety of recording apparatus using a hard disk and a magneto-optical disk as a recording medium to record information on the recording medium by rotating the recording medium are vibrated or shocked, there is then the disadvantage that the video signal cannot be recorded on the recording medium normally.